CAJ | 학술논문

刻线尺寸的器件表面存在着大量的如槽、台阶等不连续特征，当提取其基准面来做质量评定时，ISO规定最小二乘拟合法来实现，但其鲁棒性远远差于滤波法。而若直接采用传统滤波法(如高斯滤波、小波滤波等)在不连续特征处会产生波动。基于此，提出一种新的滤波稳健算法，通过对双树复小波变换(Dual-tree complex wavelet transform, DT-CWT)进行全变分最小化理论(Total variation minimization, TVM)梯度处理，即对每层的小波系数运用阈值方法进行初始化，借助投影次梯度法将TVM理论与DT-CWT相结合，不断迭代，最终增强DT-CWT在提取几何结构特征基准面的鲁棒性。仿真结果表明，所提算法与传统滤波方法相比，整个表征精度(最大重构误差和均方差)具有最优性，且评定高度也最接近理想高度。对一实测标块，无论从直观三维视图还是侧面对比图，其在阶跃处能很好地抑制波动，与标块实际加工的理论高度偏差只有0.0403μm，保证了产品的几何特征，为实际的工程应用提供了一种有效的基准提取方法。
각선척촌적기건표면존재착대량적여조、태계등불련속특정，당제취기기준면래주질량평정시，ISO규정최소이승의합법래실현，단기로봉성원원차우려파법。이약직접채용전통려파법(여고사려파、소파려파등)재불련속특정처회산생파동。기우차，제출일충신적려파은건산법，통과대쌍수복소파변환(Dual-tree complex wavelet transform, DT-CWT)진행전변분최소화이론(Total variation minimization, TVM)제도처리，즉대매층적소파계수운용역치방법진행초시화，차조투영차제도법장TVM이론여DT-CWT상결합，불단질대，최종증강DT-CWT재제취궤하결구특정기준면적로봉성。방진결과표명，소제산법여전통려파방법상비，정개표정정도(최대중구오차화균방차)구유최우성，차평정고도야최접근이상고도。대일실측표괴，무론종직관삼유시도환시측면대비도，기재계약처능흔호지억제파동，여표괴실제가공적이론고도편차지유0.0403μm，보증료산품적궤하특정，위실제적공정응용제공료일충유효적기준제취방법。
There are a lot of discontinuous characteristics such as grooves and the steps in the device surface with the groove size. The least squares fitting method is required by ISO regulation when the datum is extracted for its quality evaluation, but its robustness is far worse than filtering method. Fluctuations which are called the pseudo Gibbs phenomenon will be generated in the discontinuous surface if the traditional filtering method (such as Gaussian filtering, wavelet filtering, etc.) is used directly. A new filtering algorithm is proposed. By gradient processing the dual tree complex wavelet transform (DT-CWT) though the total variation minimization theory (TVM), which means initializing the wavelet coefficients of each layer by using the threshold value method; combining the idea of TVM with DT-CWT with projected subgradient method; continuous iteration; and finally the robustness of the DT-CWT transform in extracting the datum which has plane geometry characteristic is enhanced. The simulation results show that compared with the traditional filtering methods, the algorithm has the optimality in the characterization of precision (maximum reconstruction error and the mean square error), and its assess height is the closest to the ideal height. Assessment carried out on a real convex sticker block, fluctuations can be well restrained at steps whether from the intuitive 3D view or side contrast figure, and the geometrical characteristics of the product are ensured as the theoretical height deviation with the actual processed standard block is only 0.0403μm, and an effective reference extraction method is provided for practical engineering application.